The invention relates to a folding convertible top for motor vehicles of the type having a dimensionally stable rear window. Such a folding top has already been disclosed in German published unexamined patent application no. (DE-OS) 34 16 330, the rear window being a large-sized pane of glass. When the folding top is closed, the lower edge side of the rear window is at a substantial distance from the top cover retaining section of the bodywork, as a result of which a relatively broad strip of the fabric of the top cover is tensioned between the rear window and the retaining section. For the purposes of transversely displaceable articulation, the rear window is mounted on the bodywork by means of a guide device which has a cross section resembling a toggle lever.
When the rear window is laid flat, the upper lever arm of the guide device thus swings downward along a circular path about the axis of the intermediate joint until it rests on the lower lever arm of the guide device. As a result, the rear window, which is articulated on the upper lever arm, is displaced rearwards relative to the material retaining section of the body-work and at the same time is moved closer to the material retaining section, as a result of which the fabric strip between the rear window and the material retaining section is released from tension and laid down in folds.
Since the top cover is also released from tension to the side of the rear window as a consequence of the movement of the rear window towards the material retaining section, all that happens as a result of the procedure of displacing the rear window is a slight tightening of the fabric zones of the top cover lying laterally adjacent to the rear window.
In order to have a better view over the tail of the vehicle when the folding top is closed, it would be desirable per se to allow the lower edge side of the rear window to extend as close as possible to the material retaining section. As a result of this, however, the axis of articulation of the rear window, with the top closed, would extend at a correspondingly short distance above the material retaining section, as a result of which it would no longer be possible to achieve any significant lowering of the lower edge of the window relative to the material retaining section during opening of the top. As a consequence, the lowering of the rear window would not result in such an extensive release of tension in the fabric zones lying laterally adjacent to the rear window for a sufficient rearward displacement of the rear window to be possible, with tightening of these fabric zones in the longitudinal direction of the vehicle.
An object of the invention is to develop a folding top of the generic type described in such a manner that the lower edge side of the rear window can extend at a relatively short distance from the material retaining section when the folding top is closed and a substantial rearward displacement travel of the rear window still remains possible.
This object is achieved, according to preferred embodiment of the invention by providing an arrangement.
In certain preferred embodiment, wherein the top cover is provided with a fabric zone of variable length on each side of the rear window, the fabric zones being capable of being drawn apart by the rearward displacement of the rear window when the folding top is laid flat, and being capable of being shortened to their initial length when the folding top is erected into its closed position of use any rotary sliding articulation of a known type is, per se, suitable here as a transversely displaceable swivel fastening. In principle, it is conceivable here for the fabric zones to be of a design such as to be elastically extensible lengthwise, since fabrics of elastic rubber filaments are known per se.
In order to be able to guarantee a uniform appearance of the top cover, the fabric zones which are variable lengthwise preferably consist of sewn-in folds of the top cover fabric.
For reasons of production engineering, it is advantageous according to certain preferred embodiments to provide that the fabric folds each extend from a connecting seam between two fabric webs of the top cover.
A completely inconspicuous arrangement of the fabric folds when the top is closed ca be achieved in that the crease of the fabric folds runs, in each case, in the extension of an associated turnover crease.
A particularly simple and space-saving articulation of the rear window on the material retaining hoop is provided by using a strip of the fabric of the top cover itself which acts as a film hinge.
In the case of a folding top with a large-sized rear window which can be retracted into a top box, the rear window can be displaced in a space-saving manner almost to the rear wedge end of the material retaining hoop, as a result of which the top box itself and the top box aperture can be of especially narrow design.
A correspondingly large rearward displaceability of the rear window can additionally be achieved, in a simple manner in that the fabric strip of the top cover enclosing the circumference of the material retaining top remains unattached.
During the rearward displacement of the rear window, there occurs a sliding motion of the rear frame part of a window frame enclosing the rear window on the middle section of the material retaining hoop lying below it. In order to be able to prevent damage caused by scratching of the metal surfaces sliding upon each other and, in particular, the generation of friction noise, an arrangement of sliding means is provided in certain preferred embodiments for the sliding support of the frame part on the outer surface of the material retaining hoop.
The arrangement of sliding means preferably comprises a plurality of individual slides which, relative to the median longitudinal axis of the convertible car, are arranged in mirror symmetry on the underside of the frame part. As a result, the sliding motion can deliberately be restricted to particular sliding points.
Advantageously, the slides each consist of a mounting rail which can be removably attached to the frame part and supports a padding element, the element interacting with the material retaining hoop in a sliding relationship.
For production engineering reasons, it is advantageous to use as the padding element an extruded section of an elastic material, such as rubber or the like, which can be connected to the mounting rail by simply being pushed thereon.
In order to attach the mounting rail to a window frame which in any case has a plurality of screw connection points on the lower frame part, without any additional fixing means being needed, two screw connection points on the frame part can in each case serve simultaneously as screw fixing points for the mounting rail.
The fabric folds of the top cover can, in principle, be held in their tightened overlapping position solely by means of tensile forces in the fabric of the top cover, provided that the top is closed. However, this presupposes that the longitudinal tensile forces in the top cover, the direction of traction of which extends approximately parallel to the lateral edges of the rear window, would be much greater than the transverse tensile forces oriented in the circumferential direction of the tail region, which tend to pull the fabric folds apart.
In order reliably to prevent the gaping open of the fabric folds despite substantially uniform tensile forces in the top cover in certain preferred embodiments, each fabric fold is assigned a leaf spring element which supports the fabric folds against transverse tensile forces in the top cover, and is fixed by one end to the window frame of the rear window and by its other end to the material retaining hoop. In this arrangement, the upper end of the leaf spring element is expediently fixed by screwing to the window frame, the screw fixing point being able to be identical with an existing screw connection point on the window frame in order to avoid an additional screw fixing means.
A substantial saving of fixing means in combination with a particularly simple way of mounting the leaf spring elements is achieved if a lower end region of the leaf spring elements is bent in the form of a hook and engages securingly around the rear profile cross section of the material retaining hoop.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.